Hydrostatic Axial Piston Machine

ABSTRACT

A hydrostatic axial piston machine includes a drive shaft and a plurality of cylinder sleeves in which a spherical or ball-shaped section and a spherical or ball-shaped piston are inserted to delimit a respective displacer chamber. The sections are secured on a rotor, while the pistons are secured on a piston disk or piston drum. The piston disk is configured to be tilted at different pivoting angles relative to the rotor in a variable-displacement machine, or the piston disk is tilted continuously relative to the rotor in a constant-displacement machine. The rotor and the piston disk are coupled to one another for conjoint rotation by a driving device. The rotor and the piston disk can also be coupled indirectly by a drive shaft of the machine. A sliding joint axial with respect to a drive shaft is arranged between the rotor and the piston disk.

This application claims priority under 35 U.S.C. §119 to patentapplication no. DE 10 2013 222 602.0, filed on Nov. 7, 2013 in Germany,the disclosure of which is incorporated herein by reference in itsentirety.

BACKGROUND

The disclosure relates to a hydrostatic axial piston machine.

The known types of hydrostatic axial piston machines include not onlythe classic type of machine with an integral rotating cylinder drum butalso a type of machine in which the cylinders are arranged in revolvingcylinder sleeves. The different displacer chambers are therefore formedin individual cylinder sleeves, which are articulated on a common rotorvia respective ball joints, on the one hand, and into which respectivespherical or ball-shaped pistons are inserted, on the other hand, saidpistons being secured on a common piston disk. By setting the pistondisk obliquely to the rotor or setting the rotor obliquely to the pistondisk, the desired stroke motion of the pistons in the cylinder sleevesis produced as the cylinder sleeves revolve with the rotor and with thepiston disk. In this case, the rotor or the piston disk is secured on adrive shaft or is formed integrally therewith, wherein the drive shaftserves as an output shaft in the case of an axial piston motor and as aninput shaft in the case of an axial piston pump. Axial piston machinesof this kind require a driving device in order to synchronize the rotarymotion of the rotor and of the piston disk despite the fact of theirbeing set obliquely to one another.

Printed publication DE 10 2007 011 441 A1 discloses a double hydrostaticaxial piston machine having two groups of individual cylinder sleeves,in which toothing, a torsionally stiff bellows and a constant velocityrolling bearing clutch are shown as a driving device.

Printed publication DE 10 2012 222 850 A1 shows a hydrostatic axialpiston machine with individual cylinder sleeves, wherein a driving pininserted transversely into the drive shaft is proposed as a drivingdevice, said pin engaging in slots in a collar on an obliquely set rotordisk. A Cardan joint and a constant velocity joint are furthermoreproposed as a driving device.

In DE 10 2012 222 743 A1, a hydrostatic axial piston machine isdisclosed with individual cylinder sleeves, the obliquely set cylinderend of which is articulated by means of a Cardan joint on the driveshaft.

The disadvantage with hydrostatic axial piston machines of this kind isthat there is a rigid coupling between the rotor and the piston disk inthe direction of the drive shaft, and therefore these components cannotbe pushed apart by a mechanical force (e.g. by a preloading spring).

Given this situation, it is the underlying object of the disclosure toprovide a hydrostatic axial piston machine having individual cylindersleeves, in which this disadvantage is eliminated.

SUMMARY

The object is achieved by a hydrostatic axial piston machine having thefeatures of the disclosure.

The hydrostatic axial piston machine has a drive shaft and a pluralityof cylinder sleeves, in which a spherical or ball-shaped section, on theone hand, and a spherical or ball-shaped piston, on the other hand, areinserted in order to delimit a respective displacer chamber. Thesections are secured on a rotor, while the pistons are secured on apiston disk or piston drum. Depending on the embodiment, the piston diskand the rotor can be tilted relative to one another in avariable-displacement machine, or the piston disk and the rotor aretilted relative to one another in a constant-displacement machine. Therotor and the piston disk are furthermore coupled to one another forconjoint rotation by means of a driving device. This coupling can alsobe implemented indirectly by means of a drive shaft of the machine.According to the disclosure, a sliding joint axial with respect to adrive shaft is arranged between the rotor and the piston disk. Thisensures decoupling and axial mobility of the piston disk relative to therotor.

The axial sliding joint can have a key and a groove or toothing, forexample.

The driving device can be arranged inside or outside a pitch circle ofthe sections and pistons. At the outer circumference of the pitchcircle, the circumferential forces to be transmitted are lower, andtherefore the driving device can have comparatively small individualelements (e.g. journals). In this case, the drive shaft can becontinuous.

To support an axial preloading force, which is required between thepiston disk and the rotor, a pressure sleeve can be arranged on (e.g.pushed onto) the outer circumference of the drive shaft, said sleevehaving on its outer circumference a spherical shape against which thepiston disk or the rotor rests.

In a preferred principle of the axial piston machine according to thedisclosure, the rotor is arranged perpendicularly to the drive shaft andis connected to the latter for conjoint rotation or is formed integrallytherewith, while the piston disk can be tilted or is tilted relative tothe drive shaft.

The piston disk can be provided with a bushing-type extension, which ispart of the driving device or which is used to articulate the drivingdevice thereon.

In an illustrative embodiment which is simple in terms of device design,the driving device has a joint having just one transverse axis.According to a first variant, two journals are arranged along thetransverse axis, said journals being inserted into two mutually oppositeaxial slotted holes or grooves in such a way as to be pivotable andslidable. According to a second variant, a continuous pin is arrangedalong the transverse axis, said pin being inserted into two mutuallyopposite axial slotted holes or grooves in such a way as to be pivotableand slidable.

In a Cardan-like illustrative embodiment, the driving device has twojoints having respective transverse axes, wherein the two transverseaxes are set at 90 degrees to one another. According to a first variant,two journals are in this case arranged along each transverse axis, saidjournals being inserted into two mutually opposite axial slotted holesor grooves in such a way as to be pivotable and slidable. In this case,the two transverse axes can intersect, i.e. form a cross. According to asecond variant, a continuous pin is arranged along each transverse axis,said pin being inserted into two mutually opposite axial slotted holesor grooves.

To reduce frictional losses, laterally flattened sliding blocks orsliding bushings can be placed on end sections of the two or fourjournals or on the pin or pins, said sliding blocks being pivotable orrotatable relative to the journal or to the pin or pins about thetransverse axis and being inserted in a sliding manner into the slottedholes or grooves.

In another illustrative embodiment, the driving device has at least oneCardan joint known per se from the prior art, the central part of whichhas two transverse axes, which intersect and are perpendicular to oneanother and along each of which two journals inserted pivotably intoholes extend.

In a development of the Cardan joint, the central part thereof can be anintermediate sleeve which is annular, for example, which is arrangedbetween an outer circumference of the drive shaft of or the rotor and aninner circumference of the piston disk or the bushing-type extensionthereof. In this case, the intermediate sleeve can be connected in anarticulated manner to the rotor by means of two mutually opposite innerjournals and can be connected in an articulated manner to the pistondisk by means of two mutually opposite outer journals, for example.

Particularly in the case of relatively large tilting angles of thepiston disk, it is preferred if the driving device has a centralbushing, which, on the one hand, is articulated on the drive shaft or onthe rotor and, on the other hand, is articulated on the piston disk orthe bushing-type extension thereof. This enables the central bushing toadopt a tilt relative to the drive shaft corresponding to half the tiltof the piston disk.

In this arrangement, the two articulations can be embodied by respectiveCardan joints with intermediate sleeves as described above, for example.

The central bushing can also be articulated on the drive shaft or on therotor by means of two rotary-sliding connectors and can be articulatedon the piston disk or the extension thereof by means of tworotary-sliding connectors offset by 90 degrees relative to saidrotary-sliding connectors. The rotary-sliding connectors each have asliding block which is guided in an axial slotted hole or an axialgroove, and they each have a journal which is inserted pivotably into ahole.

In another preferred illustrative embodiment, the driving device isformed by a plurality of radially inward-directed projections, e.g.webs, which are each arranged on a cylinder sleeve and which remainengaged in axial grooves of the piston disk or of the extension thereofduring revolution or can be engaged therein during revolution in orderin this way to transmit the torque. In this illustrative embodiment, noadditional components are required for the driving device.

In another preferred illustrative embodiment, the driving device has aconstant velocity joint or homokinetic joint, which has a plurality ofballs, wherein each ball is guided in a first and a second groove.

In this case, the balls can be guided in a cage, thereby making possiblepairs of grooves which are not capable alone of determining the positionof the common ball thereof.

In another preferred illustrative embodiment, the driving device has atleast two balls or spherical segments distributed over thecircumference, which are each guided along a first straight track setobliquely to the drive shaft (or to the rotor) and along a secondstraight track set obliquely to a longitudinal axis of the piston disk.In an embodiment as a bipot joint, two mutually opposite balls orspherical segments are provided.

In this case, a pin can be provided, which extends along the firsttrack. According to a first variant, the ball or spherical segment issecured on the pin, and the pin can be moved along the first track.According to a second variant, the pin is secured on the drive shaft oron the rotor, while the ball or spherical segment can be moved along thepin and hence along the first track.

As an alternative, it is also possible for each ball to be guided alongthe first track and along the second track by two grooves in each case.

The driving device can be a tripot joint having three sphericalsegments, which are each guided so as to be movable on one of threeradial journals of the drive shaft or of the rotor, said radial journalsbeing distributed uniformly over the circumference, and which are eachguided so as to be movable in two mutually opposite axial grooves of thepiston disk.

It is also possible to provide two tripot joints of this kind, of whicha first tripot joint connects the drive shaft or the rotor in anarticulated manner to the central bushing, and wherein the second tripotjoint connects the central bushing in an articulated manner to thepiston disk.

In another preferred illustrative embodiment which is simple in terms ofdevice design, the driving device is formed by the spherical orball-shaped sections inserted in the cylinder sleeves and by thecylinder sleeves and by necks of the pistons. The necks are preferablyof tapered shape for this purpose.

In another illustrative embodiment, the driving device has a pluralityof recesses, which are distributed over the circumference of the rotor,for example, and into which corresponding pins, which are secured on thepiston disk, for example, engage during revolution.

In another illustrative embodiment, the driving device has a curvedtoothing, which is formed on the drive shaft or on the rotor, on the onehand, and on the piston disk, on the other hand. In the case of aconstant-displacement machine, the toothing can be of taperedconfiguration.

The driving device can also have a flexible element or an element whichcan be bent according to the tilt of the drum disk. This element can bea bellows, for example.

BRIEF DESCRIPTION OF THE DRAWINGS

Various illustrative embodiments of a hydrostatic axial piston machineaccording to the disclosure are described in detail below with referenceto the figures.

In the drawings:

FIG. 1 shows essential parts of a first illustrative embodiment in aschematic longitudinal section,

FIG. 2 shows a detail of a second illustrative embodiment in atransparent perspective view,

FIG. 3 shows a detail of a third illustrative embodiment in alongitudinal section,

FIG. 4 shows a detail of a fourth illustrative embodiment in alongitudinal section,

FIG. 5 shows a detail of a fifth illustrative embodiment in alongitudinal section,

FIG. 6 shows a detail of a sixth illustrative embodiment in alongitudinal section,

FIG. 7 shows a detail of a seventh illustrative embodiment in atransparent perspective view,

FIG. 8 shows a detail of an eighth illustrative embodiment in aperspective view,

FIG. 9 shows a detail of a ninth illustrative embodiment in alongitudinal section,

FIG. 10 shows essential parts of a tenth illustrative embodiment in alongitudinal section,

FIG. 11 shows a detail of an eleventh illustrative embodiment in atransparent perspective view,

FIG. 12 shows a detail of a twelfth illustrative embodiment in atransparent perspective view,

FIG. 13 shows a detail of a thirteenth illustrative embodiment in atransparent perspective view, and

FIG. 14 shows a detail of a fourteenth illustrative embodiment in aperspective view.

DETAILED DESCRIPTION

FIG. 1 shows the essential parts of a first illustrative embodiment of ahydrostatic axial piston machine according to the disclosure. It has adrive shaft 1, to which a disk-shaped rotor 2 is coupled for conjointrotation. Uniformly distributed spherical segments 4 are secured on thecircumference thereof, onto each of which segments a cylinder sleeve 6is pushed in such a way that they jointly form a ball joint. A sphericalpiston 8 is furthermore inserted into each cylinder sleeve 6, with theresult that the spherical segment 4 delimits a displacer chamber 10together with the piston 8. Each piston 8 is secured by means of a neck12 on a piston disk 14, which is set at an angle to the rotor 2 andhence to the drive shaft 1.

During revolution of the drive shaft 1 with the rotor 2, the piston disk14 and with the cylinder sleeves 6, the pistons 8 perform a strokemotion relative to the respective cylinder sleeve 6. In this case, thespherical pistons 8 are inserted pivotably in the respective cylindersleeves 6. The piston disk 14 is pushed in the direction of the rotor 2(to the left in FIG. 1) against an annular pressure sleeve 15, which ismounted on the drive shaft 1 and is supported there on a radial shoulder(not shown).

By means of an axial sliding joint according to the disclosure, which isdesigned as a groove-key arrangement 16 between the rotor 2 and thedrive shaft 1 in the first illustrative embodiment according to FIG. 1,the axial decoupling of the rotor 2 from the piston disk 14 is achieved.

Driving is accomplished by means of the displacer unit having the threecontact partners: spherical segment 4, cylinder sleeve 6 and neck 12. Inthis case, the necks 12 are configured in such a way that, at one of thepistons 8, there is always surface contact between the neck 12 thereofand the associated cylinder sleeve 6, via which the torque istransmitted. The driving piston 8 changes during one revolution of theillustrative embodiment shown in FIG. 1.

FIG. 2 shows a detail of a second illustrative embodiment of the axialpiston machine according to the disclosure in a transparent perspectiveview. The rotor (not shown in FIG. 2) is supported on the drive shaft 1by means of toothing 116. The piston disk 114 is developed to give apiston drum, which has a bushing-type extension 120. Two mutuallyopposite slotted holes 122 are introduced into said extension. A pin 124is inserted transversely into the drive shaft 1, respective slidingblocks 126 being secured rotatably on each of the end sections of saidpin which project from the drive shaft 1. The sliding blocks 126 aresecured on the pin 124 by means of wire rings 128.

The piston disk 114 is driven by means of flattened outer regions of thesliding blocks 126, which are in contact with one of two contactsurfaces of the slotted holes 122. As an alternative, the pin can alsobe secured in the rotor instead of in the drive shaft. Moreover, the pincan be introduced into the piston disk or into the extension and thecontact surfaces can be introduced into the rotor. As a supplement tothe second illustrative embodiment according to FIG. 2, it is alsopossible for two pins 124 with a total of four sliding blocks 126 to beprovided, wherein the two pins 124 are arranged crosswise relative toone another. To transmit the axial preloading force, there isfurthermore a need for a spherical cap, which is positioned between thepressure sleeve 15 and the piston disk 114, for example.

FIG. 3 shows a third illustrative embodiment according to the principleof a Cardan joint, wherein only a short section of the drive shaft 1 andonly an end section of the extension 120 of the piston disk 114 areshown. A sleeve-shaped section of the rotor 102 is shown on the driveshaft 1. An annular intermediate sleeve 130 is provided between saidsection and the extension 120. With the rotor 102, this forms a firstaxis of rotation (situated in the plane of the drawing) and, with theextension 120, it forms a second axis of rotation perpendicular thereto(arranged perpendicularly to the plane of the drawing). For thispurpose, four pins (not shown in FIG. 3) are provided, being insertedinto corresponding holes.

FIG. 4 shows a fourth illustrative embodiment, in which two Cardanjoints based on the principle of the illustrative embodiment shown inFIG. 3 and also a central bushing 132 associated therewith are provided.The two intermediate sleeves 130 are pinned to the central bushing 132perpendicularly to the plane of the drawing, thus allowing rotationabout the pin axis. A similar rotary connection, which is perpendicularthereto in each case, is established between the rotor 102 and oneintermediate sleeve 130 and between the piston disk 114 and the otherintermediate sleeve 130.

In the third illustrative embodiment and in the fourth illustrativeembodiment, axial decoupling is ensured by introducing a groove-keyarrangement 16 according to FIG. 1.

FIG. 5 shows a fifth illustrative embodiment, in which the drivingdevice is formed by a ball-type constant velocity joint. This has aplurality of balls 234, which are guided in straight axial ball races.To be more precise, each ball 234 has a first groove 236 formed in therotor 202 and a second groove 237 formed in the extension 220 of thepiston disk. All the grooves 236, 237 extend axially with respect to therespective component 202, 220, in which they are arranged. As analternative to the grooves 236, 237 shown in FIG. 5, said grooves canalso be curved.

Since the shape of the grooves 236, 237 does not unambiguously determinethe position of the associated balls 234 in the fifth illustrativeembodiment according to FIG. 5, a cage 238 is used for definite guidanceof the balls 234. The cage 238 is configured in such a way that therotation of the rotor 202 and of the piston disk take placesynchronously. The pressure sleeve 15 is provided for transmission ofthe axial force, being clamped between the rotor 202 and the cage 238.

According to another basic variant, the driving device is formed by aplurality of pots, the balls 244 of which each run on two obliquely setstraight tracks.

FIG. 6 shows an illustrative embodiment in which a plurality ofspherical segments 240 are guided in such a way as to be movable along arespective pin 241 secured on the rotor 202 and set obliquely to thelatter. Each spherical segment 240 is furthermore guided along a track242 set obliquely to a longitudinal axis of the piston disk 214. As analternative, the spherical segment can be secured on the pin, which isthen supported in an axially movable manner in the rotor. The rotor andthe piston disk can furthermore be exchanged.

FIG. 7 shows a seventh illustrative embodiment, in which a ball 244 is,on the one hand, guided along a track set obliquely to the longitudinalaxis of the rotor 202 by means of two mutually opposite grooves 245. Onthe other hand, the ball 244 is guided along the track set obliquely tothe longitudinal axis of the piston disk 214, likewise by means of twomutually opposite grooves 246. The pairs of grooves 245, 246 are formedin respective pairs of guide rails, which are inserted into the rotor202 and into the piston disk 214. A pressure sleeve 15 (not shown inFIG. 7) is used to transmit the axial force. The axial sliding joint isformed by the toothing 116.

FIG. 8 shows an eighth illustrative embodiment, in which the drivingdevice is designed as a tripot joint. In this case, three radialjournals 248 uniformly distributed over the circumference are secured onthe rotor 202, on each of which a spherical segment 240, e.g. an annularspherical segment, is rotatably supported. The extension 220 of thepiston disk 214 has three axial slotted holes, in which pairs ofmutually facing grooves 245, 246, 247 are arranged. These pairs ofgrooves 245, 246, 247 each guide one spherical segment 240. A pressuresleeve 15 (not shown in FIG. 8) is used to transmit the axial force. Itis also possible to provide a double tripot joint between the driveshaft 1 and the piston disk 214 or the extension 220 thereof, said jointconsisting of two tripot joints according to FIG. 8.

FIG. 9 shows a detail of a ninth example, in which the driving devicebetween the rotor 202 and the extension 220 of the piston disk has twoor more pins 250, which extended radially inward from the innercircumference of the extension 220. The pins 250 project intocorresponding recesses 252 in the rotor 202. Driving is in each caseaccomplished by means of those pins 250 which are in contact with therotor 202. As an alternative, it is also possible for the pins to beprovided in the rotor and for the recesses to be provided in the pistondrum or in the extension thereof. The axial forces are transmitted by aseparate component similar to the pressure sleeve 15 from FIG. 2.

FIG. 10 shows a tenth illustrative embodiment of the axial pistonmachine according to the disclosure. The rotor 302 thereof is connectedfor conjoint rotation to the drive shaft 1 by means of the toothing 116.Circular-cylindrical necks 312, on which the pistons 8 are formed, areinserted into the piston disk 314, which is tilted relative to saidshaft. Between the rotor 302 and the piston disk 314 there are twoindividual Cardan joints. The intermediate sleeves 330 thereof are bothpinned to a central bushing 332, allowing rotation about the pin axis. Asimilar rotary connection is established between the rotor 302 and theassociated intermediate sleeve 330 and between the piston disk 314 andthe associated intermediate sleeve 330. The axial preloading force canbe transmitted by means of a spring (not shown) between an axiallymovable component 354 and the piston disk 314, for example.

FIG. 11 shows a detail of an eleventh illustrative embodiment having adriving device, in which a sleeve-type extension of the rotor 302engages around an extension 220 of the piston disk. An individual Cardanjoint having two joint connections is situated between them. On the onehand, there is a rotary-sliding connection with two partners and arotary-sliding connection offset by 90° thereto in the direction ofrotation, likewise with two partners. FIG. 11 shows a solution by meansof four flattened pins 356, wherein a main section of a journal 356 anda foot section of another journal 356 are shown in FIG. 11. Each journal356 is guided on one side in a bore and on the other side in a slottedhole 122. To transmit the axial preloading force, there is furthermore aneed for a spherical cap, which is positioned between the drive shaftand the piston drum, for example.

In the illustrative embodiment according to FIG. 12, two individualCardan joints according to FIG. 11 and a central bushing 432 areprovided as a driving device. The uniform torque transmission of therotor 402 to the piston drum, of which only the extension 220 is shownin FIG. 12, is ensured by the fact that a central axis of the centralbushing 432 assumes the same angle in each case to the axis of the rotor402, on the one hand, and to the axis of the extension 220 and hence ofthe piston disk, on the other hand.

FIG. 13 shows a thirteenth illustrative embodiment, in which the drivingdevice is formed by a double Cardan of compact construction. Between therotor 402 and the extension 220 of the piston disk there is a centralbushing 532, which is connected to the rotor 402 by means of tworotary-sliding connectors 558, on the one hand, and to the extension 220by means of rotary-sliding connectors 558 arranged offset by 90°thereto, on the other hand. Each rotary-sliding connector 558 has ajournal, by means of which it is inserted into a corresponding hole, anda sliding block, which is inserted into a corresponding slotted hole122. This arrangement makes it possible to introduce the slotted holes122 in the central bushing 532 offset by 90° relative to the holes,enabling the central bushing 532 to be of compact configuration withoutsacrificing rigidity. The angular position of the central bushing 532and hence the uniform torque transmission and the transmission of theaxial preloading force are ensured as in the twelfth illustrativeembodiment according to FIG. 12.

FIG. 14 shows a fourteenth illustrative embodiment of the axial pistonmachine according to the disclosure, wherein only one cylinder sleeve606 is shown between the piston disk 314 and the rotor 402 for the sakeof clarity. On its side facing the extension 620 of the piston disk 314,each cylinder sleeve 606 has a radially inward-directed projection 660,which extends approximately along the cylinder sleeve 606. Correspondingaxial grooves 662 are introduced on the outer circumference of theextension 620, wherein the projection 660 of the associated cylindersleeve 606 engages in the groove 662, depending on its rotationalposition. In this case, the driving device is formed by the projections660 and the grooves 662 without the need to provide special componentsfor driving.

A disclosure is made of a hydrostatic axial piston machine having adrive shaft and having a plurality of cylinder sleeves, in which aspherical or ball-shaped section, on the one hand, and a spherical orball-shaped piston, on the other hand, are inserted in order to delimita respective displacer chamber. The sections are secured on a rotor,while the pistons are secured on a piston disk or piston drum. Dependingon the embodiment, the piston disk can be tilted at different pivotingangles relative to the rotor in a variable-displacement machine, or thepiston disk is tilted continuously relative to the rotor in aconstant-displacement machine. The rotor and the piston disk are coupledto one another for conjoint rotation by means of a driving device. Thiscoupling can also be implemented indirectly by means of a drive shaft ofthe machine. A sliding joint axial with respect to a drive shaft isarranged between the rotor and the piston disk.

LIST OF REFERENCE SIGNS

-   1 drive shaft-   2; 102; 202; 302; 402 rotor-   4 spherical segment-   6; 606 cylinder sleeve-   8 spherical piston-   10 displacer chamber-   12; 312 neck-   14; 114; 214; 314 piston disk-   15 pressure sleeve-   16 groove-key arrangement-   116 toothing-   120; 220; 620 extension-   122 slotted hole-   124 pin-   126 sliding block-   128 wire ring-   130; 330 intermediate sleeve-   132; 332; 432; 532 central bushing-   234 ball-   236 first groove-   237 second groove-   238 cage-   240 spherical segment-   241 pin-   242 track-   244 ball-   245, 246, 247 groove-   248 radial journal-   250 pin-   252 recess-   354 axially movable component-   356 journal-   558 rotary-sliding connector-   660 projection-   662 groove

What is claimed is:
 1. A hydrostatic axial piston machine, comprising: a drive shaft; a rotor having a plurality of spherical or ball-shaped sections arranged thereon; a piston disk having a plurality of pistons arranged thereon, the piston disk being configured to be tilted relative to the rotor or the rotor being configured to be tilted relative to the piston disk; a plurality of cylinder sleeves with each cylinder sleeve having a respective section of the rotor and a respective piston of the piston disk inserted therein to define a respective displacer chamber; and a driving device configured to couple the piston disk and the rotor for conjoint rotation, wherein an axial sliding joint is arranged between the rotor and the piston disk.
 2. The hydrostatic axial piston machine according to claim 1, wherein the rotor is arranged perpendicularly to the drive shaft and is one of connected to the drive shaft for conjoint rotation or formed integrally therewith, and wherein the piston disk is configured to be tilted relative to the drive shaft.
 3. The hydrostatic axial piston machine according to claim 1, wherein the driving device has a joint having a transverse axis, wherein two journals are arranged along the transverse axis, the journals being inserted into two mutually opposite axial slotted holes or grooves, or wherein a pin is arranged along the transverse axis, the pin being inserted into two mutually opposite axial slotted holes or grooves.
 4. The hydrostatic axial piston machine according to claim 1, wherein the driving device has two joints having respective transverse axes, and wherein the two transverse axes are set at 90 degrees to one another, and wherein two journals are arranged along each transverse axis, the journals being inserted into two mutually opposite axial slotted holes or grooves, or wherein a continuous pin is arranged along each transverse axis, the pin being inserted into two mutually opposite axial slotted holes or grooves.
 5. The hydrostatic axial piston machine according to claim 3, wherein laterally flattened sliding blocks are placed on end sections of the journals or on the pin or pins, the sliding blocks being pivotable about the transverse axis and being inserted into the slotted holes or grooves in a sliding manner.
 6. The hydrostatic axial piston machine according to claim 1, wherein the driving device has at least one Cardan joint, the Cardan joint having a central part with two transverse axes, along each of which two journals inserted into holes extend.
 7. The hydrostatic axial piston machine according to claim 6, wherein the central part is an intermediate sleeve arranged between an outer circumference of the drive shaft or the rotor and an inner circumference of the piston disk or an extension thereof.
 8. The hydrostatic axial piston machine according to claim 1, wherein the driving device has a central bushing that is articulated on the drive shaft or on the rotor and that is articulated on the piston disk or an extension thereof.
 9. The hydrostatic axial piston machine according to claim 8, wherein the central bushing is articulated on the drive shaft or on the rotor by two rotary-sliding connectors and is articulated on the piston disk or an extension thereof by two rotary-sliding connectors offset by 90 degrees relative to the rotary-sliding connectors, wherein the rotary-sliding connectors each have a sliding block that is guided in an axial slotted hole or an axial groove, and wherein the rotary-sliding connectors each have a journal that is inserted into a hole.
 10. The hydrostatic axial piston machine according to claim 1, wherein the driving device is formed by a plurality of radially inward-directed projections, the radially inward-directed projections each being arranged on a cylinder sleeve and being configured to be engaged in axial grooves of the piston disk or of an extension thereof.
 11. The hydrostatic axial piston machine according to claim 1, wherein the driving device is a constant velocity joint having a plurality of balls, and wherein each ball is guided in a first groove and a second groove.
 12. The hydrostatic axial piston machine according to claim 1, wherein the driving device has at least two balls or spherical segments that are each guided along a first track set obliquely to the drive shaft and along a second track set obliquely to a longitudinal axis of the piston disk.
 13. The hydrostatic axial piston machine according to claim 12, further comprising a pin extending along the first track.
 14. The hydrostatic axial piston machine according to claim 12, wherein each ball is guided along the first track and along the second track by two grooves, respectively.
 15. The hydrostatic axial piston machine according to claim 1, wherein the driving device is a tripot joint having three spherical segments, which are each guided so as to be movable on one of three radial journals of the drive shaft or of the rotor, the radial journals being distributed uniformly over the circumference, and which are each guided so as to be movable in two axial grooves of the piston disk.
 16. The hydrostatic axial piston machine according to claim 1, wherein the driving device is formed by the spherical or ball-shaped sections and by the cylinder sleeves and by necks of the pistons.
 17. The hydrostatic axial piston machine according to claim 1, wherein the driving device has a plurality of recesses into which corresponding pins are configured to be engaged.
 18. The hydrostatic axial piston machine according to claim 1, wherein the driving device has a curved toothing on the drive shaft or on the rotor and on the piston disk.
 19. The hydrostatic axial piston machine according to claim 1, wherein the driving device has a flexible element. 